Haplogroup G-M406

In human genetics, Haplogroup G2a3a (M406) is a Y-chromosome haplogroup. G2a3a is a branch of Haplogroup G Y-DNA (M201). More specifically in descending order, G2a3a is a subbranch also of G2 (P287), G2a (P15) and finally G2a3 (L30/S126) Haplogroup G2a3a seems most common in Turkey and Greece. Secondary concentrations of G2a3a are found in the northern and eastern Mediterranean, and it is found in very small numbers in more inland areas of Europe, the Middle East, and the southern Caucasus Mountains area.

Genetic features

A large number of G2a3a persons have the value of 21 at short tandem repeat (STR) marker DYS390, and all G2a3a men will have the M406 SNP mutation which characterizes this group. The 21 at DYS390 is uncommon among G persons outside the G2a3a group. In G2a3a persons, the DYS391 marker has mostly a value of 10, but sometimes 11, and DYS392 is almost always 11 except in one distinct cluster. If a sample meets the criteria indicated for these three markers, it is likely the sample is G2a3a.

This M406 SNP was first reported in 2008.^[1] The M designation indicates it was first identified at Stanford University. M406 is located on the Y chromosome at position 2809995, reference SNP ID i4000120. The mutation involves a change from T to G.

The SNPs L184 and L185 (respectively 17586994 with a mutation from A to G, and 20922998 with a mutation from C to G) were found to exist in only some members of a M406+ family and are now considered private SNPs with no practical use outside this family.

Age of origin of G2a3a

Research studies have not addressed the age of G2a3a. Based on available 67-marker STR samples, it would seem that the mutation that defines G2a3a arose perhaps about 4,000 years ago.

Geographical distribution

The ability to describe G2a3a distribution accurately is handicapped by the rather recent identification of the defining G2a3a SNP and the resulting paucity of samples tested for M406. Some estimate of G2a3a percentages can be made, however, by noting the percentage of men with STR marker G samples which have the distinctive 21 value at DYS390 found almost exclustively among G persons within G2a3a and making use of samples tested at commercial labs and in research papers.

Turkey and Greece

Perhaps about 5% of men in Turkey are G2a3a, the highest percentage of the general population in any country yet sampled. This 5% figure is based on the finding of the value of 21 at STR marker DYS390 in 21 of 57 G samples from throughout Turkey. Among G persons, the 21 value is seen overwhelmingly in G2a3a persons. But values other than 21 occur to a small extent in G2a3a persons. So the total G2a3a percentage within Turkish G is likely close to 50 percent, and the 57 SNP-confirmed G samples represent 11% of 523 Turkish samples obtained in the largest study yet conducted of Turkish population genetics.^[2]

In adjacent Greece, SNP testing determined that half of eight G samples were G2a3a. The G samples represented 5% of 171 Greek samples. In contrast in nearby Crete, G2a3a was only 20% of the 21 G samples, with G samples representing 11% of 193 island samples.^[1] Though treated separately in this study, Crete is part of Greece but with a different settlement history. Farther out in the Mediterranean, in a smaller sample size from Cyprus 4 of 7 G samples have the distinctive 21 value seen overwhelmingly in G2a3a persons.^[3]

Middle East

Just to the south of Turkey among the Kurds of Iraq 7 of 14 likely G STR samples in the YHRD database have the value of 21 at DYS390 suggesting half the G population there belongs to G2a3a.^[4] This relatively high percentage of G2a3a is confined to the country's northern Kurdish region.

Lebanon, Jordan and Palestine also have significant G2a3a populations though small sample sizes make broad conclusions difficult. In one study, 4 of 5 Palestinian G samples have the distinctive DYS390=21 value.^[5] In Lebanon, at least 10 of 37 G samples have G2a3a features and are found among all the major religions there.^[6] In Jordan, 7 of 15 available G samples have 21 at marker DYS390.^[3] None of the G samples among the Druze peoples in these locations have STR marker values typical of G2a3a persons according to recent studies.^[7] However, recent testing on Family TreeDNA points to some families whose origins lie in Palestine/Israel, but who have moved to Lebanon or Syria prior to the 1500-1700 period who happen to be carrying around 50-60% of the Druze among the Haplogroup G population in Druze. There is initially reasonable assurance the samples are within the DYS459=8 subgroup (that is also negative for its own DYS392=12 subgroup). Overall, these sets of related subgroups make up a major part of G2a3a men and are negative for the L14 and L645 SNP-defined subgroups. The sample has a few marker values that are a little different and the Druze samples have 22 at DYS390 compared to the more typical 21 in the majority of G2a3a samples. So this is good indirect evidence that at least half of the G among the Druze is G2a3a. In Syria, G2a3a seems less common than in the countries closer to the Mediterranean. Only 3 of 17 G samples there have the 21 value discussed.^[3]

Other areas

The largest source of G STR samples from Iran is the YHRD database where only 1 of 340 Iranian samples has a value of 21 for DYS390 together with the other marker values consistent with G2a3a samples.^[4] It is possible G2a3a persons in Iran have different STR marker values. The countries that share the Persian Gulf and Gulf of Oman with Iran were the subject of a separate small study which provided STR samples with G patterns similar to those in Iran. But the percentage of G2a3a (based on the 21 value) would seem higher than in Iran in Dubai with half of 6 G samples with 21. None of the three G samples from Yemen and Saudi Arabia had this DYS390 value.^[8]

In the Nasidze study^[9] of the Caucasus Mountains area, his 87 likely G STR samples now in the YHRD database have only 8 samples with the distinctive DYS390 value of 21 that is the overwhelming feature of the G2a3a group. Only in Georgia where 3 of 16 likely G samples have 21 does G2a3a apparently have a significant presence.^[4]

The Haplogroup G Project newsletter^[10] is gradually summarizing the percentage of G2a3a men in other areas based on the likely or proven G2a3a samples in the project's large project G database.^[11] This source has more reliability in identifying the totality of G2a3a samples because it does not rely on the value at STR marker DYS390 as the sole criterion.

The newsletter indicates (in descending order) in Italy 20% of 156 G samples......Spain 15% of 56 G samples.....Netherlands 15% of 20 G samples......Switzerland 8% of 51 G samples.....Iran 6% of 34 G samples....Poland 4% of 75 G samples......France 4% of 46 G samples......Ireland 3% of 29 G samples.......India 3% of 18 G samples.

In addition, a research study which provided Indian and Pakistani STR marker samples did not find that any of the 20 G samples from various groups contained the DYS390=21 value so typical of G2a3a.^[12] And a study of Sardinia found 7% of 51 G STR samples had the characteristic 21 value.^[13] Possibly of significance, half of these "21" samples were found in the asylum land of the ancient Sardinian population in the isolated central highlands which has no evidence of occupation by external colonial powers beginning with the Phoenician period.^[14] In the Spanish islands to the west of Sardinia, in another study none of 7 G STR samples from Ibiza are G2a3a, but 2 of 4 G samples in Majorca have the DSY390 value of 21. This same study found one 21 value among 25 G Sephardic Jews whose history is intertwined with Spain.^[15] Of the 291 STR samples of all types in the YHRD database^[16] from Egypt none of the DYS390=21 samples has the same features of known G2a3a samples from other areas of the Mediterranean.

G2a3a subgroups

G2a3a1

G2a3a1 is characterized by possessing the SNP mutation designated either as L14 or S130. G2a3a1 persons typically have DYF395S1 values of 16,16 and a DYS565 value of 11.

L14 and S130 are different designations for the same SNP mutation. The L14 version was developed at Family Tree DNA, and S130 was developed at Ethnoancestry. But this mutation was first identified at the University of Central Florida in 2006 as U16 and well before the associated researchers published a formal description in 2009 of its location at 21327383 on the Y chromosome, reference number rs35474563. The mutation involves a C to T change.^[17]

Another SNP of interest is S133 which was first identified in 2008 at Ethnoancestry in London, England in a G2a3a person, but it is also available as L90 elsewhere. Its location on the Y chromosome is given as 20087688, reference number rs35169834. The mutation is a change from G to A. In the several persons in which this mutation have been found it does not form a separate category from G2a3a1 because the tested persons also had the mutation that defines G2a3a1 (L14 or S130). It is possible there are persons who are positive (derived) for either L14/S130 while negative (ancestral) for L90/S133, and such a situation would necessitate creating a separate G2a3a category.

G2a3a2

G2a3a2 is characterized by possessing the SNP mutation designated as L645. G2a3a2 persons so far all have the value of 9 at STR marker DYS578. Both European and Near Eastern members of this subgroup have been identified. L645 was first identified at Family Tree DNA in summer 2011. It was found at chromosome position 2948673 and represents a mutation from A to C.

The DYS454=12 cluster

There is a cluster of G2a3a men not belonging to the G2a3a1 subgroup who (1) have the unusual (for G2a3a men) value of 12 at STR marker DYS454 instead of the ancestral 11 value (2) and have a relatively close genetic distance when 67 markers are compared. The shared common ancestor may have lived about 2,000 years ago or so. This DYS454 STR marker is not as reliable as a SNP mutation for categorizing men, but the 12 value plus other uncommon features and the close genetic distance make is certain this a distinct subgroup. A few persons who belong to this cluster may have had more recent ancestors who mutated to a value other than 12, but such samples have not surfaced.

Many men in this cluster have developed one or two other mutations at STR markers which make the cluster even easier to identify. The largest number of cluster men have a mutation at DYS459a from the ancestral 9 to 8. And many have a mutation from the ancestral 11 to 12 at DYS392. The DYS392=12 value is seen almost exclusively in G1 persons, with this G2a3a cluster being a major exception.

This cluster seems overwhelmingly made up of three identifiable ethnic groups (a) Ashkenazi Jews based on distinctive surnames together with ancestral origins in northeastern Europe south of Scandinavia, (b) Conversos with Hispanic surnames and (c) Men with Italian ancestral origins. However, an available sample from Iran also likely belongs to this cluster. The Ashkenazi Jews are so far not found in the group with the ancestral 11 at DYS392. And the Hispanics are so far not found within the DYS392=12 group. (See also page covering Jews with Haplogroup G (Y-DNA)).

The DYS459b=10 cluster

The men in this cluster of G2a3a men do not belong to the G2a3a1 subgroup and have (1) the unusual (for G2a3a men) value of 10 at STR marker DYS459b instead of the ancestral 9 value (2) and have a relatively close genetic distance when 67 markers are compared. This is so far a relatively small cluster with French and British ancestral histories. Too few samples are available to estimate with some reliability when the common male ancestor of this cluster may have lived.

The DYS436=14 cluster

The men in this cluster of G2a3a men do not belong to the G2a3a1 subgroup and have the unusual (for G2a3a men) value of 14 at STR marker DYS436 instead of the ancestral 12 value This is so far a relatively small cluster with ancestral histories confined to Galicia and Basque country in Spain and to various parts of Portugal. Too few samples are available to estimate with some reliability when the common male ancestor of this cluster may have lived.

Migrations of G2a3a persons

It is logical that G2a3a spread westward along the Mediterranean from the area where it is most concentrated today (Turkey and the eastern Mediterranean countries) in conjunction with the trading, slave-selling and other migratory events originating in these lands. The first great trading empire that joined both ends of the Mediterranean was the Phoenician that originated in the Israel-Lebanon-Jordan area. After the demise of the Phoenicians, the Greeks, Romans, Byzantines and some "barbarians" could have spread G2a3a from the eastern Mediterranean to the west.

In comparisons of 67-marker G2a3a STR samples^[11] available from inland Europe with similar samples from (1) Turkey (2) Lebanon-Jordan and (3) Armenia certain deductions can be made. Most G2a3a Europeans have Armenians as their nearest relatives. Based on the number of mutations observed, some of these probably share common male ancestors as recently as the Dark Ages. Only one European showed Jordan/Lebanon samples as the nearest G relatives. Likewise none of the Europeans showed Turks alone as nearest relatives, but rather some European samples had Turks and Armenians equally related.

The sharing of common ancestors much farther back in time (perhaps 3,500 years ago) among some of these samples does not provide information so useful because the migration westward could have occurred anytime in the earlier period. The finding of likely G2a3a samples in the ancient isolated highlands of Sardinia, however, suggests the arrival of G2a3a in that island prior to the arrival of the Phoenicians. The latter began a Sardinian coastal presence about 3,000 years ago.

There is currently no information to explain the dispersion of G2a3a to the southern Indian area.

See also

• genetic genealogy
• Y-DNA haplogroups by ethnic groups
• Haplogroup G (Y-DNA) Country by Country

References